Strip exposure apparatus for nucleation medium

ABSTRACT

A strip exposure apparatus to provide exposure strips at the edge of a nucleation film to control the use rate of the zinc atoms in the film developer. The edge exposure strip is controlled by a video integrator which integrates each line of video information and writes the inverse of this signal on the edge of the film.

United States Patent Sullivan et al.

Sept. 2, 1975 NUCLEATION MEDIUM STRIP EXPOSURE APPARATUS FOR [56] References Cited UNITED STATES PATENTS Inventors: Paul A. Sullivan, Santa Monica; 2,883,257 4/1959 Wehe 346/74 R George G. Vitt, ,ln, Los Angeles, 3,462,762 8/1969 Kaspaul et a1 346/74 CR both of C lif 3,660,087 5/1972 Kaspaul et al. 96/1 R 3,671,238 6/1972 Kaspaul et a1. The United Stat s of America as 3,736,142 5 1973 Kaspaul et al. 96/1 R Assignee:

represented by the Secretary of the Air Force, Washington, DC.

Feb. 4, 1974 Filed:

Appl. No.: 439,672

Primary ExaminerRaymond F. Cardillo, Jr. Attorney, Agent, or Firm--Wi1liam Stepanishen; Joseph E. Rusz ABSTRACT 178/6'6 R; 178/6'6 R; 178/6? R; A strip exposure apparatus to provide exposure strips 346/74 CR at the edge of a nucleation film to control the use rate Int. Cl. of the i atoms i the pe The dge e Field of Search 178/66 R, 6.7 R, 6.7 A;

346/74 CR, 74 EB, 74 R, 176 R; 96/1 R,

posure strip is controlled by a video integrator which integrates each line of video information and writes the inverse of this signal on the edge of the film.

8 Claims, 7 Drawing Figures I4- I6 l2 3 F57 fv aza aw v I 77 a SW17? 5 24: 375 Mt tyw/rrh I a; 2 2 iflwnw c w 0 I (M r804 3 0! runmm 4 6 78/66 a 2e (M r8044 L 2 A 2 I 535155 SW22 LEVEL 1 "Q ML swieP 0 cwv 1804 (t/Munro:

A M HNK/A/ a UR l/Rz fit 55F 0o V!I /f00 n 5 3Lfi/VK/IV6 4 min v/ala on o m wricuz 01' W)! if a *11" ll Wiufnrlung g n ['1 r [writ/1A fl Q D 00 N710 I. WAVEFdR/l/S PATENTEDSEP' 2191s SHEET 1 [IF 2 w mjm a 3 E F SHEET 2 Of 2 PATENTEUSEP 21975 STRIP EXPOSURE APPARATUS FOR NUCLEATION MEDIUM BACKGROUND OF THE INVENTION The present invention relates broadly to nucleation medium recording and in particular to edge strip exposure apparatus to improve image reproducibility.

The selective deposition of materials, particularly metals, upon a preconditioned or prenucleated recording medium is relatively well known in the prior art. One of the advantages of nucleation recording medium is its ability to be rapidly developed within the vacuum environment of an electron beam recorder. In a device with a film speed of a few millimeters per second, the zinc vapor development process must be confined to a few mm along the length of film in order to achieve rapid access to the recorded imagery. One prior art method of achieving this result is through the use of a moving wall developer. However, the amount of film within such a developer at any instant is very small. The developed density of the image has been found to be dependent upon the average amount of image exposure. The density versus exposure data for the nucleation film was found to be nonreproducible when the film was developed in this apparatus. This is due to the fact that the film image areas do not extract zinc atoms from the developer region at the same rate that they are produced by the developer. If the developer provides zinc atoms at a constant rate, it would be possible to minimize spurious development effects by recording at a constant average level. The present invention provides a strip exposure apparatus for recording a strip at each edge of the film where the exposure level may be continuously varied inversely with the average video information level. In this manner, the use rate of zinc by the film would remain a constant and greater reproducibility of image development would be realized.

SUMMARY The present invention utilizes a strip exposure apparatus to provide exposure strips at the edge of the film in an electron beam recorder using 70 mm wide nucleation film. The exposure strips are produced along a 5 mm edge space at each edge of the 60 mm image. This edge strip exposure is controlled by a video integrator which integrates each line of video information and writes the inverse of this signal at the end of the line and at the beginning of the next line. The integrator is then discharged in preparation for integrating the next line of video information.

It is one object of the invention, therefore, to provide an improved strip exposure apparatus wherein the use rate of the zinc vapor developer is a constant.

It is another object of the invention to provide an improved strip exposure apparatus wherein the exposure level of the nucleation recording medium is continuously varied inversely with respect to the average video information level.

It is yet another object of the invention to provide an improved strip exposure apparatus to provide greater image reproducibility within the nucleation recording medium.

These and other advantages, objects and features of the invention will become more apparent from the following description taken in connection with the illustrative embodiment in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of the strip exposure apparatus in accordance with the present invention,

FIG. 2 is a schematic diagram of the video integrator and switch circuit, and,

FIGS. 3a-e are a graphical representation of signals at various points within the video integrator and switch circuit.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, there is shown a block diagram of the edge strip exposure apparatus for a nucleation recording medium. The present invention provides exposure strips at the edge of the film which is used in an electron beam recorder using mm wide nucleation film. The exposure strips are produced along a 5 mm edge space at each edge of the 60 mm image. This edge strip exposure is controlled by a video integrator which integrates each line of video information and writes the inverse of this signal at the end of the line and at the beginning of the next line. The integrator is then discharged in preparation for integrating the next line of video information.

There is shown in FIG. 1, an input terminal 10 which applies the video input signal to the FET switch 12 and the video select unit 14. When control signal D enables the FET switch 12, the video input signal is applied to integrator unit 16 to be integrated. The output of the integrator unit 16 applied to the video select unit 14 where either the video or the integrated video signal is allowed to pass through the FET switch, depending upon the state of control signal B. The output signal from the FET switch 14 is utilized in an electron beam recorder to write either the video signal or the exposure control strips (the integrated video signal) upon the nucleation film. A retrace blanking control unit 20 which receives the system blanking signal provides a retrace blanking signal to mixer 22. A sweep level comparator which receives the system horizontal sweep signal utilizes preset signals VRl, VR2, to provide a sweep level output signal to mixer 22. A reset trigger unit 26 is utilized to reset integrator unit 16 at the beginning of each new video line in order to integrate the next line of video information which is presented for recording.

Turning now to FIG. 2, there is shown a schematic diagram of the video switch and integrator circuit. It is the function of the present circuit to time share between direct video and the integral of the video. The direct video is gated on during a preselected portion of the scan period which is determined by the setting of the window comparator U1. The window width is by adjusting R and R which establishes the compare voltage VRl and VR2 with the sweep input voltage on pin 16. During the window period, the video input on Pin 17 is enabled to pin 12 (video output) through the analog switch U2, and enabled to the integrating amplifier U4 through analog switch U3. At the end of the window period the integrating amplifier U4 is placed in a hold condition (by the action of analog switch U3), and its output voltage will appear at pin 12 by the action of analog switch U2. The output level of integrating amplifier U4, attained during the integration period, is set to be equal to the average half amplitude value of the input video (resistor R performs this function). If the input video is zero, the output of integrating amplifier U4 will be maximum, but as the video increases to maximum amplitude, the output ofintegrating amplifier U4 will decrease toward zero.

The hold period of integrating amplifier U4 remains until the next window period. As a result, the integral of the incoming video will be painted on the recording film at the end of one scan and the beginning of the next one. At the start of the next window period, a one shot multivibrator U5 is triggered on and activates the analog switch U6 which discharges the integrating capaciter C4. The period of the one shot US, which is controlled by the setting of resistor R. is set long enough to completely discharge capacitor C4 l0 usec typical).

The circuit devices which are utilized in the present invention are conventional devices having standard part numbers. The window comparator Ul has the part number uA7l l. The analog switches U2, 3 and 6 have the part number SN3002. The integrating amplifier U4 has the part number ,u.A74l and the monostable switch US has the part number 9601. These conventional devices are commercially available (under their standard part numbers) from any of the various semiconductor device manufacturers, such as Fairchild Semiconductor, Mountain View, Calif, 94040.

Video blanking (+4 V pulse from the deflection amplifier) is applied through transistors Q1 and Q2 and is used to mask out the compare signal from window comparator Ul during the horizontal retrace.

Representative signals at various points of the video integrator and switch circuit are shown in FIGS. 30-30. The sweep input signal a at pin 16 (FIG. 3) will be 3.50 V peak-to-peak for 70 mm deflection ofa kV beam. This signal is supplied by the sweep generator. The sweep repetition period T F,T is the interval between synchronization pulses applied to the sweep generator. The sweep time T T is set by the sweep time control. The blanking signal b at pin 9 (FIG. 3a) will be a pulse with a 2 to 3 V amplitude from the end of the sweep to the beginning of the next sweep T to T The comparator output signal, 4', at the collector of transistor, Q1 (FIG. 3b) is about 4 V whenever the sweep input is between the two voltage values set with resistors R1 and R5. These values are set so that the switching times T and T are between T, and T The video signal is switched through analog switch U2 during the interval T to T At T analog switch U2 switches to the inverse integral signal to record the density compensating edge strip. Nominally, the intervals are T -T,=T r,-T =(T -T,)/ 14 to record 5 mm edge strips during the 70 mm wide scan. The blanking signal is summed with this signal at transistor 01 to mask out the comparator pulse that occurs at T when the sweep signal retraces through the two compare voltages. The

comparator signal (FIG. 3b) is applied to the monosta-.

ble switch US through transistor Q2. A capacitor discharge pulse d (FIG. 3b) appears at pin 8 of monostable switch US at time T The pulse duration T -T is set with resistor R This pulse closes analog switch U6 which short-circuits capacitor C4 to reset the integrator to zero.

The video signal is applied to the integrator from T to T through analog switch U3. The integrator ramp which appears at TPS is shown in FIGS. 30, d, and e as signals e, g and i respectively. Signal e, FIG. 30, is the integrator ramp which appears at TF5 (test point 5, FIG. 2) as a result of a O.5 volt input at TP2 (test point 2, FIG. 2). There is shown in FIG. 3d, signal g, the integrator ramp at TPS which is the result of l .5 volts video input at TP2. There is shown in FIG. 3e, signal 1', an integrator ramp at TPS which is the result of 2.5 volts video input at TP2. The integrated signal level is held by capacitor C4 from T4 to T5 (and T to T For a minimum video signal (O.5 V at pin 17) U4 integrates to 2.5 V and for a maximum video signal (2.5 V at pin 17) integrating amplifier U4 integrates to O.5 V. Switch U2 passes this integrated video signal during the intervals T to T and T to T and passes the video signal from T to T, as shown by the video output signals f, h andj respectively of FIGS. 30, d and e.

Although the invention has been described with reference to a particular embodiment, it will be understood to those skilled in the art that the invention is capable of a variety of alternative embodiments within the Spirit and scope of the appended claims.

What is claimed is.

l. A strip exposure apparatus for a nucleation recording medium comprising in combination:

means for selecting a video signal and an integral video signal, said selecting means providing an output signal upon receipt of a control signal, said output signal being either said video signal or said integral video signal, integrating means receiving a video signal, said integrating means integrating said video signal to provide an integral video signal, said selecting means being connected to said integrating means to receive said integral video signal therefrom, and

control means connected to said selecting means and said integrating means, said control means providing a control signal to said selecting means to select either said video signal or said integral video signal as an output, said control means resetting said integrating means prior to the start of the next line of video information, and

means for recording on a nucleation medium, said nucleation medium having a first and second section, said recording means being connected to said control means to receive said control means output, said recording means recording said video signal on said first section of said nucleation medium, said recording means recording said integral video signal on said second section of said nucleation medium.

2. A strip exposure apparatus as described in claim 1 wherein said selecting means comprises an analog switch having a first and second input terminal, said first input terminal receiving a video signal, said second input terminal receiving said integral video signal, said video signal being gated through said analog switch during a first predetermined time of the video scan period, said integral video signal being gated through said analog switch during a second predetermined time of the video scan period.

3. A strip exposure apparatus as described in claim 2 wherein said first predetermined time is longer than said second predetermined time.

4. A strip exposure apparatus as described in claim I wherein said integrating means comprises an integrating amplifier to integrate said video signal, said integrating amplifier providing an integral video signal to said selecting means, and,

an analog switch to apply said video signal to said integrating amplifier, said analog switch being switched in relation to the video scan period.

5. A strip exposure apparatus as described in claim 4 wherein said integral video signal is inversely proportional to the average video signal.

6. A strip exposure apparatus as described in claim 1 wherein said control means comprises a window comparator to provide said first and second predetermined time of said video scan period, said window comparator receiving a first and second compare voltage, said window comparator utilizing said first compare voltage to provide said first predetermined time, said window comparator utilizing said second compare voltage to provide said second predetermined time, said window comparator providing a first control signal to said selecting means to select said video signal, said first control signal enabling said integrating means, said window comparator providing a second control signal to said selecting means to select said integral video signal.

7. A strip exposure apparatus as described in claim 6 further including a monostable switch, said monostable switch being triggered by said window comparator to reset said integrating amplifier.

8. A strip exposure apparatus as described in claim 7 further including a retrace blanking signal summed with said window comparator output signal to remove a spurious pulse during the retrace portion of the video 

1. A strip exposure apparatus for a nucleation recording medium comprising in combination: means for selecting a video signal and an integral video signal, said selecting means providing an output signal upon receipt of a control signal, said output signal being either said video signal or said integral video signal, integrating means receiving a video signal, said integrating means integrating said video signal to provide an integral video signal, said selecting means being connected to said integrating means to receive said integral video signal therefrom, and control means connected to said selecting means and said integrating means, said control means providing a control signal to said selecting means to select either said video signal or said integral video signal as an output, said control means resetting said integrating means prior to the start of the next line of video information, and means for recording on a nucleation medium, said nucleation medium having a first and second section, said recording means being connected to said control means to receive said control means output, said recording means recording said video signal on said first section of said nucleation medium, said recording means recording said integral video signal on said second section of said nucleation medium.
 2. A strip exposure apparatus as described in claim 1 wherein said selecting means comprises an analog switch having a first and second input terminal, said first input terminal receiving a video signal, said second input terminal receiving said integral video signal, said video signal being gated through said analog switch during a first predetermined time of the video scan period, said integral video signal being gated through said analog switch during a second predetermined time of the video scan period.
 3. A strip exposure apparatus as described in claim 2 wherein said first predetermined time is longer than said second predetermined time.
 4. A strip exposure apparatus as described in claim 1 wherein said integrating means comprises an integrating amplifier to integrate said video signal, said integrating amplifier providing an integral video signal to said selecting means, and, an analog switch to apply said video signal to said integrating amplifier, said analog switch being switched in relation to the video scan period.
 5. A strip exposure apparatus as described in claim 4 wherein said integral video signal is inversely proportional to the average video signal.
 6. A strip exposure apparatus as described in claim 1 wherein said control means comprises a window comparator to provide said first and second predetermined time of said video scan period, said window comparator receiving a first and second compare voltage, said window comparator utilizing said first compare voltage to provide said first predetermined time, said window comparator utilizing said second compare voltage to provide said second preDetermined time, said window comparator providing a first control signal to said selecting means to select said video signal, said first control signal enabling said integrating means, said window comparator providing a second control signal to said selecting means to select said integral video signal.
 7. A strip exposure apparatus as described in claim 6 further including a monostable switch, said monostable switch being triggered by said window comparator to reset said integrating amplifier.
 8. A strip exposure apparatus as described in claim 7 further including a retrace blanking signal summed with said window comparator output signal to remove a spurious pulse during the retrace portion of the video scan period. 